Conventionally, as an immunoassay device which can detect a material to be detected present in a specimen solution with high sensitivity, a device (SPFS device) for a surface plasmon-field enhanced fluorescence spectroscopy (SPFS) using SPR is known (for example, Patent Documents 1 and 2).
In an SPFS device of Patent Document 1, a plurality of metal thin films are provided in an array on a planar portion of a dielectric block (dielectric member) which is used for SPFS; a plurality of capture regions on which a sensing material binding to a specific material (material to be detected) is formed on each of the plurality of metal thin films are formed; a light beam which is emitted from a light source in a state of a divergent light is parallelized; and a plurality of capture regions each of which is in contact with a sample is irradiated with the parallel light simultaneously, whereby a large number of materials to be detected can be analyzed in tandem with each other.
In an SPFS device of Patent Document 1, however, since detection processings are performed simultaneously for a plurality of sensing regions, detection sensitivity becomes lower than those in cases in which a detection processing is individually performed for one sensing region, which is problematic. Since sensing regions are adjacent with each other, there is a problem of an influence by a crosstalk due to adjacent sensing regions. Therefore, like the SPFS device of Patent Document 1, a plurality of sensing regions are simultaneously detected, the detection cannot be performed with high sensitivity, which is problematic.
On the other hand, Patent Document 2 relates to a sensor chip for SPFS having a dielectric member, in which each of a plurality of capture regions for detecting a material to be detected is formed such that shortest distances from a plane of incidence of the dielectric member are the same, thereby minimizing unevenness in measurement data of a fluorescence signal between a plurality of capture regions and improving measurement accuracy.
Since the SPFS device of Patent Document 2 is a device which performs a detection processing by shifting a projector (light source) with respect to each of a plurality of capture regions to individually irradiate a plurality of capture regions, detection is possible with a higher sensitivity than a device in which detection processings are simultaneously performed with respect to a plurality of capture regions as in Patent Document 1. With the SPFS device of Patent Document 2, however, the order of a plurality of capture regions on each of which a detection processing is performed is not determined, and in addition, transition of a detection processing action from one capture region to another capture region takes some amount of time, and therefore, a detection processing is not performed in the order matching a purpose of detection such as a purpose of detecting with high accuracy, whereby a detection result which should naturally be obtained is not obtained, which is problematic.